D-Psicose is one of monosaccharides called rare sugar. Because the sugar was hardly available in the past since the sugar could not be produced at a mass scale, almost no research works about the physiological activity and pharmacological activity of the sugar were done. In recent years, a mass-scale process of producing D-psicose with an enzyme has been developed by Izumori, et al. at the Agricultural Department, Kagawa University, so that the biological activity thereof has been elucidated.
Compared with monosaccharides such as D-glucose and D-fructose, D-psicose has been drawing attention as a sugar never promoting fat synthesis or never accumulating body fats, particularly intraperitoneal fat (non-patent reference 1). Additionally, a report tells that the effective energy value of D-psicose is almost zero (non-patent reference 2). Highly possibly, a process of producing D-psicose in a form of a crystalline sugar complex containing D-fructose will be established (patent reference 1). Therefore, an application of D-psicose as a sweetener is expected.
Concerning the physiological activity and pharmacological activity of D-psicose, the patent reference 1 includes a report telling that examinations were made using D-psicose and the intestinal tract about the influence of the ketohexose belonging to rare sugar on glucose absorption since foods are digested to decomposed so that glucose is absorbed in the intestine for supply; an action of D-psicose to mildly suppress blood glucose level was verified in an animal (rat), so that it was verified that D-psicose had an action of decreasing blood glucose at hyperglycemia and an action of promoting insulin secretion and that D-psicose hardly triggered protein saccharification. The patent reference 1 describes that it was demonstrate that the ketohexose belonging to rare sugar had an action of stimulating insulin secretion from pancreatic β cell and an action of enhancing insulin secretion at hyperglycemic states and that the ketohexose belonging to rare sugar will therefore expectantly be a substance with a new action mechanism never found conventionally; additionally that the ketohexose belonging to rare sugar promotes insulin secretion in patients with diabetes mellitus to ameliorate the blood glucose level; that the ketohexose belonging to rare sugar after enteral administration suppresses glucose absorption and the ketohexose belonging to rare sugar never influences sugar metabolism, which suggests that the ketohexose possibly suppresses post-meal hyperglycemia in diabetes mellitus so the ketohexose is expectantly a substance advantageous for the prevention or therapeutic treatment of diabetes mellitus; that it is observed that the ketohexose belonging to rare sugar is effective for preventing arteriosclerosis in significant relations with diabetes mellitus and complications thereof and the main cause of death due to diabetes mellitus is an arteriosclerotic disease, so the ketohexose belong to rare sugar and having an action of suppressing arteriosclerosis is expectantly an innovative therapeutic agent of diabetes mellitus to ameliorate the blood glucose level and prevent arteriosclerosis; and that the ketohexose belonging to rare sugar is expectantly a health supplementary food with such therapeutic effects and an anti-obesity action.    Non-patent reference 1: Matsuo T., et al., Asia Pacific J. Clin. Nutr. 10, 233-237, 2001    Non-patent reference 2: Matsuo T., et al., J. Nutr. Sci. Vitaminol 48, 77-80, 2002    Patent reference 1: International Patent Application WO 03/097820    Patent reference 2: JP-A-2001-11090